The Soča (pronounced [ˈsoːtʃa] in Slovene) or Isonzo (in Italian) (other names Friulian: Lusinç, archaic German: Sontig, Latin: Aesontius or Isontius) is a 138-kilometre (86 mi) long river that flows through western Slovenia (96 kilometres or 60 miles) and northeastern Italy (43 kilometres or 27 miles).An Alpine river in character, its source lies in the Trenta Valley in the Julian Alps in northwestern Slovenia, at an elevation of 876 metres (2,874 ft).